GRN and frontotemporal dementia: The role of GRN-deficiency in FTD has prompted interest in the development of PGRN-based therapies by, for example, increasing PGRN levels in the brain (Arrant et al., 2017, 2018; Miyakawa et al., 2020), or promoting read-through of GRN non-sense mutations (Frew et al., 2020; Kuang et al., 2020).